The present invention is in a casting resin on the basis of methacrylic acid ester, filled with aluminum hydroxide or hydrated aluminum oxide, and plastic objects and moldings manufactured therefrom.
Plastic objects and moldings made from casting resins filled with aluminum hydroxide or hydrated aluminum oxide on a basis of methacrylic acid esters are known (cf. U.S. Pat. Nos. 3,644,735 and 3,847,865). Such plastic objects and moldings display fire-resistance, special optical properties, and resistance to acids.
It is furthermore known to add organic silicon compounds and other additives to casting resins on a basis of methacrylic acid esters which are filled with silicatic fillers. In this manner the working properties of these resins and the practical properties of the plastic objects and moldings made therefrom are decidedly improved (cf. DE-PS No. 24 49 656 and EP-A No. 0 107 764).
The working properties of casting resins filled with aluminum hydroxide or hydrated aluminum oxide on a basis of methacrylic acid esters and the practical properties of plastic objects and moldings made therefrom are either not improved or are insufficiently improved by known organosilicon compounds and other additives.
A high degree of filling is necessary, combined with low viscosity for the broad application of casting resins filled with aluminum hydroxide or hydrated aluminum oxide on a basis of methacrylic acid esters. A high degree of filling guarantees the fire-proof quality of the plastic objects and moldings made from the resins and reduces the shrinkage in the curing of the resins to an acceptable degree. At the same time, low viscosity is necessary in order to manufacture geometrically attractive plastic objects and moldings. Furthermore, for a broad application, it is necessary that plastic objects and moldings, manufactured from the casting resins retain their practical properties, such as resistance to boiling, acid resistance and mechanical properties, even under permanent stress. In many cases, a higher level of the mechanical properties is also necessary.